Cost of Removing Japanese Knotweed

Last updated 14th March 2022

Want to know how much you’d need to pay to have Japanese knotweed removed?

In this article we’ll discuss the price of getting rid of Japanese Knotweed, the cost factors involved, and the steps required to remove Japanese knotweed among other topics.

Japanese knotweed sprouting

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What Does It Cost to Remove Japanese Knotweed?

The average cost of removing a 20m2 domestic area of knotweed infestation is £400 to £2100, while to remove a 20m2 to 50m2 area would cost approximately £1800 to £3300. As for a 50m2 to 100m2 area, expect to pay around £3200 to £5200 altogether.

What about for a commercial site area with an infestation?

As for herbicide treatment over a five year time frame, you’re likely to pay £1000 to £3200 if it’s for an area of 50m2 or less. When it comes to a 50 to 100m2 area, expect a charge of between £3000 and £5500. When it comes to a 100 to 500m2 area, it costs about £4000 to £7000 but for a 500m2 to 1000m2 area, this would be priced at around £5000 to £10,000 or more.

Looking at the process of reducing dig and root barriers with the use of herbicide treatments, for this fix you’d be footing a bill of around £2000 to £5500 for an area of 50m2 or less. In the case of a 50m2 to 100m2 area, this would cost roughly £5000 to £12,000. In the case of a 100m2 to 500m2 area, the price would be roughly £20,000 to £40,000, while you could expect a cost of £40,000 or more if the area is anywhere from 500m2 to 1km2.

maintaining a garden

The same prices as above would apply in the case of pick and sort/screening. When it comes to onsite relocation and herbicide, this costs around £5000 to £12,000 for a 50m2 or less. In terms of a 50m2 to 100m2 area, this would cost about £10,000 to £20,000 but the price would hit £15,000 to £30,000 for a 100m2 to 500m2 area and likely somewhere between £20,000 and £30,000 in the case of a 500 to 1000m2 location.

In terms of a burial on site, this costs about £5000 to £15,000 for an area of 50m2 or less, £10,000 to £20,000 in the case of a 50m2 to 100m2 commercial site, £20,000 to £35,000 if such an area is 100m2 to 500m2, and the cost would be about £30,000 to £80,000 for a 500m2 to a 1000m2 location.

Finally, with regards to a total excavation and disposal (dig and dump), this would cost approximately £5000 to £20,000 for a 50m2 area or less, £15,000 to £40,000 for a 50m2 to 100m2 location, £40,000 to £120,000 with a 100m2 to a 500m2 area, or £100,000 to £200,000 for a 500m2 to a 1000m2 commercial site.

The cost depends on:

  • Ease of access
  • Type/size of Japanese knotweed
  • Equipment used

Japanese Knotweed Removal Prices

Size of Area Cost
20m2 or less £400 to £2100
20-50m2 £1800 to £3300
50-100m2 £3200 to £5200


Removal for a Commercial Site

Task 50m2 50-100m2 100m-500m2 500m-1000m2
Herbicide Treatment Through 5 Years £2000 to £5500 £5000 to £12,000 £20,000 to £40,000 £40,000 or more
Reduce Dig & Root Barriers (using Herbicide Treatments) £1000 to £3200 £3000 to £5500 £4000 to £7000 £5000 to £10,000
Pick and Sort/Screening £2000 to £5500 £5000 to £12,000 £20,000 to £40,000 £40,000 or more
Onsite Relocation (using Herbicide) £5000 to £12,000 £10,000 to £20,000 £15,000 to £30,000 £20,000 to £30,000
Onsite Burial £5000 to £15,000 £10,000 to £20,000 £15,000 to £30,000 £20,000 to £30,000
Total Excavation and Disposal (Dig and Dump) £5000 to £20,000 £15,000 to £40,000 £40,000 to £120,000 £100,000 to £200,000


Additional Costs

There are plenty of extra jobs you may want to fit in after the Japanese knotweed is removed or treated. Let’s take a look at some popular examples.

Garden Maintenance

There are various forms of garden maintenance that may feature in such work such as hedge and bush trimming/pruning, weed removal, leaf blowing, grass cutting, lawn feeding, watering, as well as patio/driveway cleaning.

It costs about £10 to £50 an hour to hire a gardener for said work. The actual price is going to depend on the size of the area as generally speaking the larger the area, the more it will cost.

Here’s an example of some prices:

  • 6x4 metres - £50 to £300
  • 8x6 metres - £50 to £400
  • 12x8 metres - £100 to £800

Garden Fencing

Fencing is a great way to enhance the look and feel of a garden, especially if you bland structures currently in place.

Here are some average costs of fencing:

  • Lap fence panels - £400 to £600
  • Slatted fence panels - £500 to £700
  • Decorative panels - £700 to £1000
  • Tongue and groove panels - £800 to £1200

As for some alternative fencing types:

  • Wire - £1 to £5
  • Electric - £3 to £10
  • Picket - £5 to £10
  • Vinyl - £15 to £30
  • Aluminium - £20 to £30
  • Steel - £20 to £40

Cost Breakdown Calculator

Individual costs for removing Japanese knotweed by dig and dump for a 50-100m2 area – Total Cost: £27,400

95%

Materials
£26,000

4%

Tradesmen
£1100

1%

Waste Removal
£300

Labour Costs and Time Frames

Let’s now discuss the labour costs specifically and how long it takes for tradespeople to undertake this work. It costs around £20 to £50 an hour to remove Japanese knotweed. You could expect the cost to end up somewhere between £200 and £500 if you were looking to have it removed from a domestic property.

As for a small area of 50m2 or less, whether it be an industrial or domestic space, the cost could be somewhere between £100 and £250. As for a 50m2 to 100m2 area, you’d be looking at a labour price of around £200 to £500. This would land about £300 to £700 for a 100m2 to 500m2 or £400 to £1000 in the case of a 500m2 to 1000m2 location.

person weeding a garden

But how long would the work take?

On average, this is the work duration of removing Japanese knotweed:

  • Onsite relocation + herbicide - 1-2 days
  • Herbicide treatment over the course of 5 years - several years
  • Pick and sort/screenings - 1-2 days
  • Reduce dig and root barriers using herbicide treatments - 1-2 days
  • Onsite burial - 1-2 days
  • Total excavation and disposal (i.e. dig and dump)

The following factors may influence the labour cost and time frame:

  • Size/type of Japanese knotweed
  • Ease of access
  • State of the work area

Cost Affecting Factors of Removing Japanese Knotweed

As with any trades work, there are a variety of factors that could shape the price of having Japanese knotweed removed. We’ve mentioned some of these factors already but let’s now look at them in more detail.

Type/Size of Knotweed

When it comes to the size and type of Japanese knotweed, this is relevant as some forms of this knotweed are more challenging to remove than others (and could involve higher supply costs). The difficulty of removal and the size of the area being relevant due to the time frame involved is a cost factor because the longer the work takes, the higher the labour costs tend to be.

bushes of Japanese knotweed

Removal Area

Ease of access and the state of the work area are important since these factors influence the time the work will take and potentially the supply costs. Once again, the longer the work lasts, the higher the labour prices (generally).

Property Location

Where you live should also be considered when budgeting for Japanese knotweed removal.

But why is this?...

In essence, each region of the UK has varying trade costs (since the living costs of said trades people differ depending on the place). Labour prices are usually highest in the southeast (London being one of the dearest spots), while they tend to be lower than the nationwide average in locations such as the north of England, Scotland, and Northern Ireland.

What Does Removing Japanese Knotweed Entail?

The exact process of ridding a property of Japanese knotweed will differ significantly depending on the method employed. We’ll focus on a given popular chemical-based approach in this section.

1. Hiring a Professional

First and foremost, you’ll want to find a suitable contractor/company for the job. It’s worth getting three or more quotes from potential candidates for the job before making a decision. This will help increase your chances of securing good value for money. Also it’s worth asking for references from an individual or company before hiring a professional.

2. Japanese Knotweed Identification

Before the contractor can get to work, they’ll need to spot the Japanese knotweed plants and verify where it is and isn’t found throughout the property.

3. Remove the Canes and Apply Weed Killer

Next up, the professional will rid the canes by cutting them off as close to the ground as can be achieved before removing the cut pieces from the property. Then, in this given method, they would spray a glyphosate-based weed killer straight after they’ve cut the canes down. It’s important that the weed killer is ONLY applied to the Japanese knotweed as any other vegetation it touches would be killed in the process.

Removing Japanese knotweed canes

4. Completing the Process

Ideally, the contractor/company should give it seven days before pulling up the weeds. This would allow the herbicide sufficient time to get to the roof of the knotweed. Then the dead knotweed can be removed. It’s important that the entire root is removed.

Following this, you should mow the plants on a weekly basis to ensure that the Japanese knotweed does not return. It’s important that you avoid touching the knotweed, however. If you do so by accident you should wash your hands with soap.

Applying the glyphosate once is unlikely to be enough, however. For that reason, a professional should apply this weed killer about twice annually. It’s ideal for this to be applied about the time when the knotweed would thrive the most.

It is possible that after all this effort, the issue will remain. In this case, you’d need to have a professional take another more stringent approach. Obviously it’s essential that you weigh up options first when it comes to the approach taken to remove the Japanese knotweed, although a hired professional will likely decide on this and know what approach is best.

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DIY Japanese Knotweed Removal

It is possible to remove Japanese knotweed flowers DIY but it is generally best to hire a specialist, given that this is complex work and requires a meticulous approach.

However, if you’d rather do it yourself, then you should still seek a professional’s advice and ensure you obtain any required approvals when it comes to building regulations and planning permission.

someone removing weeds from garden with trowl

Of course, if you’re going to remove Japanese knotweed, it’s essential that you’re sure you know precisely what is involved.

The following tools/equipment may be needed depending on the method:

  • Garden spade/shovel
  • Lawn mower
  • Spray bottle
  • Pliers
  • Handheld garden sprayer

As for the materials required, they may be:

  • Binliner
  • Glyphosate-based herbicides
  • Water

The following safety clothes/equipment should be used:

  • Protective eyewear
  • Protective shoes
  • Rubber gloves

As with any DIY work, there are some risks involved. Make sure to avoid touching the knotweed as best as possible. Either way, you should wash your hands thoroughly afterward with soap and make sure you haven’t brought any into the house with you. Also the use of sharp/heavy equipment and tools represent further hazards.

Building Regulations and Planning Permission for Japanese Knotweed Removal

Want to know what rules might apply for removing Japanese knotweed?

Building regulations and planning permission are unlikely to apply unless you intend to perform some structural changes to the location. If in doubt, you should contact your local council for verification.

Building regulations approval costs around £100, while this plus a relevant inspection would total about £300 to £500. As for planning permission approval, this is priced at around £200 to £300, although it will really depend on the nature/specifics of the job among other factors.

FAQs

Japanese knotweed comprise creamy-white tassels that can reach as much as six inches high as well as leaves with a heart or shovel shape and tall canes that resemble bamboo. Be careful not to confuse Japanese knotweed for similar looking plants such as ornamental bistorts, bindweed, and lesser knotweed.
This form of knotweed grows dramatically and is highly resilient. It is an aggressive weed that can cause serious issues for a property through damage. It can grow by as much as 10cm a day! It can find masonry cracks and weak spots in structures and in turn you can have serious Japanese knotweed damage to such buildings.
It usually takes up to a year depending on the method used but it may take as much as five years or even more.
This plant is an invasive weed that grows rapidly. It is a type of herbaceous perennial plant.
No. Because of its harmful qualities, this weed should never be disposed of at a regular dump. You should face prosecution if you do so.
You can do so by bringing it to a permitted landfill site for Japanese knotweed disposal. If you contact the Environmental Agency, they may be able to help you locate the nearest suitable site to you.

How to Find & Hire a Japanese Knotweed Removal Specialist

It is usually best practice to hire a specialist to remove Japanese knotweed as per the reasons mentioned earlier. To rehash, a Japanese knotweed removal specialist is likely to charge around £20 to £50 per hour, although it will depend on factors such as your location.

You should consider the following when hiring a Japanese knotweed removal specialist:

  • Do they have qualifications?
  • What is their experience? (ask for references)
  • How about accreditation?
  • And insurance?

While qualifications/certifications are not needed to remove Japanese knotweed, a contractor may have training in the area such as through a PCA course.

Sources

https://www.inciner8.com/blog/invasive-plants/how-to-get-rid-of-japanese-knotweed/
https://www.knotweedservices.co.uk/japanese-knotweed-removal-costs/
https://www.wandsworth.gov.uk/rubbish-and-recycling/waste-and-recycling-a-z/japanese-knotweed/
https://www.gov.uk/guidance/prevent-japanese-knotweed-from-spreading
https://www.japaneseknotweed.co.uk/japanese-knotweed-diy

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